<%#
 Copyright 2013-2020 the original author or authors from the JHipster project.

 This file is part of the JHipster project, see https://jhipster.github.io/
 for more information.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-%>
package <%= packageName %>.security.oauth2;

import org.springframework.security.jwt.crypto.sign.SignatureVerifier;

/**
 * Abstracts how to create a {@link SignatureVerifier} to verify JWT tokens with a public key.
 * Implementations will have to contact the OAuth2 authorization server to fetch the public key
 * and use it to build a {@link SignatureVerifier} in a server specific way.
 *
 * @see UaaSignatureVerifierClient
 */
public interface OAuth2SignatureVerifierClient {
    /**
     * Returns the {@link SignatureVerifier} used to verify JWT tokens.
     * Fetches the public key from the Authorization server to create
     * this verifier.
     *
     * @return the new verifier used to verify JWT signatures.
     * Will be null if we cannot contact the token endpoint.
     * @throws Exception if we could not create a {@link SignatureVerifier} or contact the token endpoint.
     */
    SignatureVerifier getSignatureVerifier() throws Exception;
}
